Someone please explain a singularity to me?

Question

I understand the concept of a singularity: an infinitesimally small and dense piece of matter with zero dimension.

Let's use an example of a black hole that started as a star, then collapsed into a black hole upon burning all of its hydrogen/helium. Obviously, this object contained a large number of particles to begin with. My question is, what becomes of all the particles after it has collapsed (and theoretically continues to collapse into a smaller and smaller space forever)? Do the particles themselves continue to shrink, or does the black hole transform into pure energy?

I thought that the consensus was that nothing could be smaller than the Planck length. If this is true, then how could the black hole continue to shrink forever?

Thanks.

Answer 1

The concensus is that our rules of physics only apply down to the Planck length. Smaller than that, we do not know what goes on.

This does not mean things can't get smaller.

However, it means that we can no longer use words like things, particles, energy, collapse... and hope that they still have meanings that we can understand.

As to what happens to the "whatever" that forms the singularity, there are various hypotheses (they are not really theories, since we do not know how to test them... yet).

Answer 2

This is best explained by string theory. (or at least a lay version) and fractal math.
There are multiple dimensions. They are arranged on a continuum and are not discrete and seperate. Mathematically, there is a zero dimension, called a point, that exists, but has no width, height, or length. Dimension 1 would be a line that has length but no width. Dimension 2 would be a plane
Dimension 3, a space, and dimension 4, a hyperspace.
under the right conditions, an object from any dimension can be warped toward another dimension.
consider a string. Held under tension, it represents a line or a 1 dimensional object. curled into a flat coil on a table, it approximates a 2 dimensional object, Wadded into a ball it represents a 3 dimension object. This warping can go either way.
A singularity is a 3dimensional object that is warped to an almost 0 dimensional object.
clear as mud... right?

Answer 3

My knowledge in this is miniscule, but I *thought* that this length was derrived from three values:

Speed of light in a vacuum, something else that escapes me and the Gravitational constant.

If I remember rightly the "constant" isn't, it is variable - and as such as the black hole becomes denser, it was my understanding that the GC would also change - and as a result the Planck length was no longer a constant either.

I shall be interested to see more learned answers on this one.

Mark

Answer 4

This is an area of active research in physics. And by research I mean speculation, since we can neither create nor observe a singularity.

Our current quantum mechanical models are simply insufficient to explain "what" exactly is present at the center of a black hole. We call it a "singularity" for mathematical simplicity, but if we try to apply any of our physical laws to it, we get nonsensical results.